With the above code, anytime the order of columns in the SQL statement or stored procedure changes, the code is broken. And if you have lots of columns to read from, it’s a real nightmare to maintain the indexes.

The next time you write another DataReader loop, consider doing it this way instead:

Using GetOrdinal makes the code much more readable and maintainable. You are calling GetOrdinal just once for each column, any performance penalty is insignificant compared to the benefits. Be careful not to put the GetOrdinal code inside the while block as that will unnecessarily slow you down (about 3% according to this article).